Rotary drill bit



INVENTOR ATTORNEYS Feb. 9 1926.

' L. G. GATES ROTARY DRILL BIT Filed July 16 1923 a ya@ Apw Mw i m xl/ fr),

v sss i n, f O AIV i Patented Feb. 9, 1926.

' LEROY G. GATES, OF BAKERSFIELD, CALIFORNIA.

ROTARY DRILL BIT.

Application filed July-16, 1923. Serial No. 651,758.

Bakersfield, in the county of Kern and State of California, have invented certain new and useful Improvements 1n Rotary Drill Bits, of which the following is a specification.

My invention relates to rotary bits for drilling wells.

The objects of my invention are to pro vide a rotary drill bit which may be operated successfully at high speeds, and which will retain a sharp and effective cutting face throughout the entire life of the bit. A further object is to provide a drill bit which is adapted for removing a section or sections of core from the well, to permit examination at the surface, of the formation in which the bit is working.

My improved drill bit is capable of etticent operation at speeds of 250 revolutions per minute and higher, which is the maXimum speed which is at present being attempted, and is therefore particularly adapted for direct connection with an electric motor located above ground, or with an electric or fluid operated motor .located yin the well immediately above the bit and suspended by a stationary drill stem. On account of the form of my bit, it can be used at the high s eeds referred to with a circulating mud uid, without expending unnecessary power in whirling or churning the mud.

The form and construction of my drill bit may be varied considerably from that shown in the accompanying rhawings and hereinafter described, without departing from the spirit of the invention as expressed in the claims hereto appended.

With this in view, a preferred embodiment of my invention will now be fully de scribed with reference to the accompanying drawings, wherein i Fig. l is a part sectional perspective view of my improved rotary drill bit.

Fig. 2 is a transverse section of the same, taken on the line 2-2 of Fig. l.

In the drawings, thereference numeral 1 designates the outermost of a plurality of cylindrical shells which form the body of the drill bit the inner shells being designated b l fdr connecting said shells to the drill stem or motor shaft. Said shank is provided and 1" respectively, and 2 is a shank .witlra central bore 3. which extends to the interior of the shell 1 as shown in Fig. l,

for the purpose of conducting `mud fiuid thereinto. It is to be understood that the lower or discharge end of the bore 3 may assume any desired form, in order to direct the issuing mud fluid in the desired manner.

Each of the shells is provided with a plurality of perforations 4, which may have various desired shapes and positions. These perfor-ations not only provide means of escape for the mud Huid, but also provide a notched or serrated lower edge for the drill body, as shown at 4 which constitutes the cutting face of the bit. This cutting face, moreover, remains notched or serrated, and 'therefore effective, throughout the life of the bit. because as said face wears away,

fresh perforat-ions are intercepted, and eachy such intercepted perforation forms a new notch in said cutting face. Y

Each of the shells is provided, both eX- teriorly and interiorly, with lateral projections, which may be of any desired form and formed with or secured to said shells in any suitable manner. In the drawings these lateral ,-,rojections are shown as helically directed ribs 5, formed integrally with the shells, and are for the purpose of providingv sufficient clearance between the shells and the bore and cores in which they are rotatf ing, to prevent binding. l

The shells may be provided interiorly with suitably formed transverse cutters 6, for cutting and breaking up4 the core formed within each of said shells by its downward boring into the formation.v If desired, the

transverse core cutters 6 may be olnittedor removed, and any well known form of core lifter, not shown 1n the drawings, may be used in connection with the drill bit in the usual manner, for the purpose of removing entire section-s of the core for examination. This process is well known in the art of well drilling, and is referred to herein'nierely to emphasize the adaptability of my drill bit to such core taking.

It is to be noted that, on account of the cylindrical construction of mydrill bit and its plurality of shells, the bit is well adapted for working in hard formation, no power is wasted in churning or whirling the mud fluid and cuttings carried thereby, and on account of the laterally projecting clearance ribs 5, the friction between the non-cutting portions of the bit and the sides of the bore is reduced to a minimum. Thus iny drill bit is capable ot' elicient operation at speeds considerably in excess ot' those now employed. Moreover, on account of the perlorations 4, the cutting edge or edges of the bit remain effective until the entire bit is worn away.

I claim:

l. A rotary drill bit comprising a plurality of spaced substantially cylindrical concentric shells, each having a cutting face and each shell having a plurality of per,- lorations in its wall.

L. A rotary drill bit comprising a plurality of spa-ccd substantially cylindrical concentric shells, each having a cutting face formed at one end and each shell having a plurality of perforations in its wall; and lateral projections extending from the surfaces of each shell.

3. A rotary drill bit comprising a plurality of connected substantially cylindrical concentri: shells. each having a cutting face and each shell having a. plurality of perforations in its wall; and 'transverse core cutters carried by and between the shells.

4. A rotary drill bit comprising a plurality of connected substantially cylindrical concentric shells, each having a cutting face 'formed at one end, and each shell having a plurality of perforations in its Wall; lateral projection-s extending from the'surfaces of each shell; and transverse core cutters carried by and between the shells.

5. A rotary drill bit comprising a plurality of substantially cylindrical concentric shells, connected together at their upper ends and spaced apart at their lower ends, each shell having a cutting face at itslower end and a plurality of perforations in its wall.

6. A rotary drill bit comprising a plurality of substantially cylindrical concentric shells spaced apart at their lower ends, the upper end portions of all said shells being integral, and each shell having a cutting face at its lower end and a plurality of apertures in its Wall.

In testimony whereof I have signed my name to this specification.

LEROY G. GATES. 

